Easy.
1. Education.
The ability to educate the young with efficiency faster.
This is the number one issue. Why?
It is the foundation of human civilization.
We are born with zero knowledge.
We live max around 120 years.
This means our civilization is generational. Meaning you can have a max of 8 generations present on earth at the same time. That generation of 8 grow and progress based off of eachother coupled with recorded history.

^ This is foundation of human civilization.
In one cycle of generations we could be reduced to tribes with no knowledge of where we came from aside from stories.

2. To advance beyond our selves. I have spoken of it, an it is spoken of rarely by ascetics yet is sometimes mentioned. Not that it is kept secret, simply nobody knows.
The body lives for the same reason it ages.
It can be rejuvenated.
Humans have the ability to become supra human.
An dare I say, mammals have this ability. Yet it takes conciouse doing. SO although natural it is indeed still a manipulation taking knowledge or accidental fate. rejuvination is like a drop in a cup. 1 drop. 3 drops. 10 drops will not make you immortal. Yet fill the cup, on longevity may be possible.
physiologically. This even isn't a "cold" rejuvination. It is a physical, experiential, psychological fire. Why fire? Well because heat is literally involved. An enormous amount of it.

Anyway. First part deals with logical advancement of society as we are today and what it will take.
Second part is our physiological potential to be discovered by society.